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       1                 :             : /* Coordinate ELF library and application versions.
       2                 :             :    Copyright (C) 1998, 1999, 2000, 2002, 2015 Red Hat, Inc.
       3                 :             :    This file is part of elfutils.
       4                 :             :    Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
       5                 :             : 
       6                 :             :    This file is free software; you can redistribute it and/or modify
       7                 :             :    it under the terms of either
       8                 :             : 
       9                 :             :      * the GNU Lesser General Public License as published by the Free
      10                 :             :        Software Foundation; either version 3 of the License, or (at
      11                 :             :        your option) any later version
      12                 :             : 
      13                 :             :    or
      14                 :             : 
      15                 :             :      * the GNU General Public License as published by the Free
      16                 :             :        Software Foundation; either version 2 of the License, or (at
      17                 :             :        your option) any later version
      18                 :             : 
      19                 :             :    or both in parallel, as here.
      20                 :             : 
      21                 :             :    elfutils is distributed in the hope that it will be useful, but
      22                 :             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      23                 :             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      24                 :             :    General Public License for more details.
      25                 :             : 
      26                 :             :    You should have received copies of the GNU General Public License and
      27                 :             :    the GNU Lesser General Public License along with this program.  If
      28                 :             :    not, see <http://www.gnu.org/licenses/>.  */
      29                 :             : 
      30                 :             : #ifdef HAVE_CONFIG_H
      31                 :             : # include <config.h>
      32                 :             : #endif
      33                 :             : 
      34                 :             : #include <libelfP.h>
      35                 :             : #include <pthread.h>
      36                 :             : 
      37                 :             : /* Multiple threads may initialize __libelf_version.
      38                 :             :    pthread_once() ensures that __libelf_version is initialized only once. */
      39                 :             : once_define(static, version_once);
      40                 :             : 
      41                 :             : /* Currently selected version.  Should be EV_CURRENT.
      42                 :             :    Will be EV_NONE if elf_version () has not been called yet.  */
      43                 :             : unsigned int __libelf_version = EV_NONE;
      44                 :             : 
      45                 :       16660 : static void initialize_version(void)
      46                 :             : {
      47                 :       16660 :   __libelf_version = EV_CURRENT;
      48                 :             : }
      49                 :             : 
      50                 :             : unsigned int
      51                 :       16660 : elf_version (unsigned int version)
      52                 :             : {
      53         [ -  + ]:       16660 :   if (version == EV_NONE)
      54                 :             :     return EV_CURRENT;
      55                 :             : 
      56         [ +  - ]:       16660 :   if (likely (version == EV_CURRENT))
      57                 :             :     {
      58                 :             :       /* Phew, we know this version.  */
      59                 :             : 
      60                 :             :       /* Signal that the version is now initialized.  */
      61                 :       16660 :       once(version_once, initialize_version);
      62                 :             : 
      63                 :             :       /* And return the last (or initial) version.  */
      64                 :       16660 :       return EV_CURRENT;
      65                 :             :     }
      66                 :             : 
      67                 :             :   /* We cannot handle this version.  */
      68                 :           0 :   __libelf_seterrno (ELF_E_UNKNOWN_VERSION);
      69                 :           0 :   return EV_NONE;
      70                 :             : }
      71                 :             : INTDEF(elf_version)